Method and apparatus for thoracoscopic intracardiac procedures

ABSTRACT

Devices, systems, and methods are provided for accessing the interior of the heart and performing procedures therein while the heart is beating. In one embodiment, a tubular access device having an inner lumen is provided for positioning through a penetration in a muscular wall of the heart, the access device having a means for sealing within the penetration to inhibit leakage of blood through the penetration. The sealing means may comprise a balloon or flange on the access device, or a suture placed in the heart wall to gather the heart tissue against the access device. An obturator is removably positionable in the inner lumen of the access device, the obturator having a cutting means at its distal end for penetrating the muscular wall of the heart. The access device is preferably positioned through an intercostal space and through the muscular wall of the heart. Elongated instruments may be introduced through the tubular access device into an interior chamber of the heart to perform procedures such as septal defect repair and electrophysiological mapping and ablation. A method of septal defect repair includes positioning a tubular access device percutaneously through an intercostal space and through a penetration in a muscular wall of the heart, passing one or more instruments through an inner lumen of the tubular access device into an interior chamber of the heart, and using the instruments to close the septal defect. Devices and methods for closing the septal defect with either sutures or with patch-type devices are disclosed.

CROSS-REFERENCE TO RELATED APPLICATIONS

This is a division of application Ser. No. 08/425,179, filed Apr. 20,1995 pending, which is a continuation-in-part of application Ser. No.08/163,241, filed Dec. 6, 1993 now U.S. Pat. No. 5,571,215, which is acontinuation-in-part of application Ser. No. 08/023,778, filed Feb. 22,1993 now U.S. Pat. No. 5,452,733.

FIELD OF THE INVENTION

The present invention relates generally to less-invasive surgery of thecardiovascular system. More specifically, the invention relates tothoracoscopic devices and techniques for performing surgical procedureswithin the heart and great vessels while the heart is beating.

BACKGROUND OF THE INVENTION

Tens of thousands of people are born each year with congenital defectsof the heart. Some of the more common types of congenital cardiacdefects include atrial septal defect (ASD), ventricular septal defect(VSD), and patent ductus arteriosis (PDA). An ASD is a hole in thecardiac septum between the left and right atria, while a VSD is a holein the septum between the left and right ventricles. Patent ductusarteriosis is incomplete closure of the opening between the pulmonaryartery and the aorta that is present during fetal development. Theseconditions may cause blood to abnormally shunt from the right side ofthe heart to the left side of the heart without being properlyoxygenated in the lungs, so that the body tissues supplied by the bloodare deprived of oxygen. In addition, blood in the left side of the heartmay shunt back to the right side through the defect rather than beingpumped into the arterial system, causing abnormal enlargement of theright chambers of the heart.

ASD's, VSD's and PDA can frequently be surgically repaired withsignificant success. Smaller defects may be reparable by simply suturingthe defect closed, while larger defects may require a patch ofpolyester, expanded polytetrafluoroethylene, or a portion of thepatient's own pericardium to be sutured into the heart to cover andocclude the defect.

Ordinarily, such surgery is performed using open-chest techniques whilethe heart is under cardioplegic arrest and circulation is maintained bycardiopulmonary bypass. Using such techniques, a gross thoracotomy iscreated in order to gain access to the heart and great vessels,facilitating clamping and cannulation of the aorta for inducingcardioplegic arrest, and allowing instruments to be introduced into thechest cavity and into the heart to perform the surgical repair. Thenecessity of stopping the heart significantly heightens the risksattendant such procedures, particularly the risks of causing ischemicdamage to the heart muscle, and of causing stroke or other injury due tocirculatory emboli produced by aortic clamping and vascular cannulation.In addition, the creation of a gross thoracotomy produces significantmorbidity and mortality, lengthens hospital stay and subsequentrecovery, increases costs, and worsens the pain and trauma suffered bythe patient. Moreover, many congenital defects are repaired in childrenunder the age of ten years for whom the morbidity and mortality ofopenchest surgery and cardioplegic arrest can be even greater than forolder patients.

In an effort to avoid the necessity of grossly opening the chest andstopping the heart, a number of intravascular devices have beendeveloped for repair of ASD's, VSD's, and PDA. For example, U.S. Pat.No. 3,874,388 to King et al. discloses an intravascular deliverycatheter introduced intraluminally from a peripheral vein into the rightside of the heart which can be used to position an artificialumbrella-like patch across a septal defect and to anchor the patch tothe cardiac septum. Other intravascular delivery devices and artificialpatches for the repair of septal defects can be seen in U.S. Pat. No.5,334,217, U.S. Pat. No. 5,284,488, U.S. Pat. No. 4,917,089, U.S. Pat.No. 4,007,743, and PCT Application No. PCT/US92/10141.

While intravascular approaches to the repair of congenital defects mayprovide certain advantages, the most significant of which is theelimination of the need for gross thoracotomy and cardioplegic arrest,these techniques have suffered from a number of problems. One suchproblem is the difficulty in manipulating the artificial patches intoposition across a defect using only the proximal end of a long andflexible delivery catheter positioned through a tortuous right lumen.Also problematic is the inadequacy of fixation of endovascularly-placedpatches, creating a tendency of such patches to migrate or embolizeafter placement, which can allow blood to again shunt through thedefect. In addition, once such a patch has been placed and the deliverycatheter detached from the patch, relocating and repositioning the patchwith the catheter is difficult, if not impossible, and may require opensurgical correction. Moreover, in young children, the size of theperipheral vessels is extremely small, and damage to such vessels couldhave serious effects upon the growth of the child. Thus, the size of thedevices which can be introduced through such vessels is greatly limited.

In addition to ASD, VSD, and PDA, various other types of cardiac diseasealso may be diagnosed and treated by intervention within the interiorchambers of the heart. For example, some cardiac arrhythmias such asventricular tachycardias, supraventricular tachycardias, and atrialfibrillation, may be diagnosed by obtaining access into an interiorchamber of the heart and by performing electrophysiological mapping toidentify abnormal conduction pathways. Once these abnormal conductionpathways are identified, in some cases the disease may be treated byablating selected cardiac tissue using radiofrequency (RF) energy or amedical laser to eliminate the abnormal pathways. A number ofendovascular approaches have been developed which attempt to allowintracardiac mapping and ablation using catheters introducedtransluminally from peripheral vessels into the heart. Such devices aredisclosed, for example, in U.S. Pat. Nos. 4,960,134, 4,573,473,4,628,937, and 5,327,889. However, endovascular mapping and ablationdevices suffer from many of the same problems suffered by endovascularseptal defect repair devices, including a lack of control and precisepositionability from the proximal end of these highly flexible andelongated devices, the significant size constraints of peripheralvessels, and the inability to position the devices in all potentiallydiseased sites within the heart.

What are needed, therefore, are devices and methods to enable the repairof ASD, VSD, PDA, and other congenital defects, as well as cardiacarrhythmias and other diseases of the heart, which eliminate the needfor gross thoracotomy and cardioplegic arrest, but which overcome theforementioned problems with intravascular techniques. The devices andmethods should facilitate a high level of control for precisemanipulation within the heart. The devices and methods should produce aseptal defect or PDA repair which is reliable and long-lasting, andshould not be susceptible to migration, embolization, or reopening of adefect. The devices and methods for septal defect and PDA repair shouldallow the position of a repair patch to be inspected after initialplacement and to be repositioned if necessary. Finally, the devices andmethods should not risk damaging the peripheral vessels of the patient,nor should the size and configuration of the devices be limited by thesize of the patient's peripheral vessels.

SUMMARY OF THE INVENTION

The invention provides devices and methods that facilitate thoracoscopicaccess into the interior of the heart while the heart is beating. Thisintracardiac access can be used to perform a variety of diagnostic andtreatment procedures within the heart without the need for a grossthoracotomy or cardioplegic arrest. The invention provides devices andmethods for the performance of a number of different proceduresincluding the repair of ASD, VSD, PDA, and other cardiac abnormalities,electrophysiological mapping and ablation for the treatment of cardiacarrhythmias, as well as a variety of other intracardiac procedures thatcan be performed thoracoscopically on a beating heart.

In a first aspect of the invention, a tubular access device is providedfor accessing an interior chamber of a beating heart. The access deviceincludes an elongated tubular body configured to extend percutaneouslythrough an intercostal space between the ribs of the chest and through amuscular wall of the heart, and an inner lumen extending through thetubular body which provides an access channel into the heart. In anexemplary embodiment, the tubular access device has a length of at least10 cm, and the inner lumen has a diameter of at least 5 mm. Preferably,the tubular access device is rigid to facilitate responsive and precisepositionability from its proximal end.

In one embodiment, the access device includes means near a distal endthereof for sealing peripherally around a surrounding penetration in themuscular heart wall through which the access device is positioned. Thesealing means may comprise one or a pair of inflatable balloons, aradially-expandable portion of the tubular body, or a flange at thedistal end of the body. A purse string suture or other tissue-gatheringmeans may be applied to the muscular heart wall surrounding the tubularbody and tightened to prevent blood from flowing through the penetrationaround the access device.

The invention may further include an obturator positionable within aninner lumen of the tubular access device. The obturator may have meansat its distal end for penetrating the muscular wall of the heart. Thepenetrating means may comprise a blade, radiofrequency electrode, orother type of cutting element. In a preferred embodiment, the obturatorfurther includes means for selectively exposing the penetrating means,which may include a movable actuator for extending and retracting thecutting means from the distal end of the obturator.

The access device may include a hemostasis valve in the inner lumen toprevent blood flow out of the heart through the inner lumen, and toallow instruments to be introduced through the inner lumen whilemaintaining hemostasis in the inner lumen. The hemostasis valve may bedisposed at either the proximal end or the distal end of the accessdevice. Alternatively, when the access device is utilized in thelower-pressure right atrium, right ventricle, or left atrium, the accessdevice may be positioned in a generally vertical orientation so thatblood flow through the inner lumen is prevented by the pressure head ofblood within the inner lumen being greater than the pressure in thecardiac chamber, eliminating the need for a hemostasis valve.

With the access device positioned through an intercostal space andthrough a wall of the heart, a straight and relatively large channeldirectly into the interior of the heart is available for theintroduction of devices for diagnostic and treatment procedures. In apreferred embodiment, the invention provides systems and methods forrepairing atrial and ventricular septal defects through the inner lumenof the access device. The septal defect repair system includes, inaddition to the above-described access device, a closure means forclosing or occluding the septal defect, and a means for introducing theclosure means through the access device into the interior of the heart.

In a first embodiment, the closure means comprises a patch that may beattached to the cardiac septum to cover and occlude the septal defect.The patch includes a collapsible frame, and a flexible patch materialattached to the frame. The flexible patch material may be an artificialbiocompatible material such as polyester or expandedpolytetrafluorethylene, or a portion of the patient's pericardium orother natural body membrane. The frame is configured to support thepatch material at its outer edges in a generally flat configuration, andis sufficiently rigid to retain its shape against the pressure of bloodwithin the heart, while having sufficient flexibility and resiliency tobe collapsible for introduction through the inner lumen of the accessdevice. In an exemplary embodiment the frame comprises a hub and aplurality of spokes extending radially outward from the hub. Acircumferential wire or suture thread extending between the outer tipsof the spokes may be provided to continuously support the outer edges ofthe patch. The hub is a rigid material such as stainless steel, is smallenough to fit within the inner lumen of the access device, and isconfigured to be detachably coupled to the distal end of an deliveryshaft (described below). The spokes are flexible, resilient wires ofNitinol™ or other material exhibiting similar super-elasticcharacteristics. The patch may be mounted to the frame by sutures, heatwelding, adhesive, or other means.

The patch includes a means for securing the patch to the cardiac septum.The securing means may comprise a second patch coupled to a centralportion of the first patch and parallel thereto such that one patch maybe positioned through the septal defect on the left side of the cardiacseptum and the second patch positioned on the right side of the cardiacseptum, with the outer edges of the two patches compressively engagingthe cardiac septum between them. For example, in the hub and spokeembodiment describe above, two sets of spokes may be mounted to the huband a patch mounted to each set of spokes so that the two patches aregenerally parallel to each other and spaced slightly apart.Alternatively, the securing means may comprise a plurality of flexiblewire struts coupled to a central part of the frame such that the outerends of the struts will compressively engage the cardiac septum on theside opposite that on which the patch is positioned. Like the patch, thesecuring means is collapsible to allow introduction through the innerlumen of the access device. To facilitate secure fixation to the septum,the frame or the securing means may include pins or spikes pointinggenerally perpendicular to the patch to partially penetrate the cardiacseptum when the patch has been positioned across the defect, preventingmigration of the patch.

The patch is introduced into the heart and positioned across the septaldefect by means of a rigid delivery shaft which may be positionedthrough the inner lumen of the access device. The delivery shaftincludes an interior lumen or aperture at its distal end for receivingthe patch and securing means in a collapsed configuration. The deliveryshaft further includes a means for deploying the patch and the securingmeans, which may comprise a rod slidably disposed in a lumen through thedelivery shaft. The rod includes means at its distal end for releasablycoupling to the patch, such as a threaded extension which couples to athreaded hub in the patch frame. The rod may be advanced distallyrelative to the delivery shaft to deploy the patch from the apertureinto the heart chamber on the side of the cardiac septum further awayfrom the point of introduction, e.g., the left atrium if the device hasbeen introduced into the heart through the right atrium. The patch ispositioned against the septum, and the securing means is deployed on theside of the cardiac septum opposite the patch, e.g., the right atrium inthe aforementioned case. The rod may then be decoupled from the patchand the delivery shaft is removed from the patient through the accessdevice.

Advantageously, the delivery shaft and deployment means are configuredto allow the patch to be re-collapsed and repositioned if the positionof the patch is not satisfactory after initial deployment. In oneembodiment, the rod is drawn proximally relative to the delivery shaft,whereby the patch is collapsed by engagement with the distal end of thedelivery shaft. The patch securing means may be collapsed in a similarmanner, or by a separate mechanism. In an exemplary embodiment, one ormore wires or sutures extend through a lumen in the delivery shaft andare coupled to the securing means, e.g. to the outer ends of the spokesor struts of the securing means. By exerting tension on the wires, thesecuring means is drawn proximally into a collapsed configuration toallow it to be received in the aperture in the delivery shaft. Thisallows the patch and securing means to be drawn back into the aperturein the delivery shaft and redeployed at the desired position.

In an alternative embodiment, the septal defect closure means comprisesa suturing device for applying at least one suture across the septaldefect. The suturing device includes a rigid delivery shaft suitable forintroduction through the inner lumen of the access device, and aplurality of needle holders mounted to the delivery shaft for releasablyholding at least two needles connected by a suture thread. The needleholders are movable between a contracted position suitable forintroducing the needles through the septal defect into the cardiacchamber on the opposite side of the septum, and an expanded position inwhich the tips of the needles are aimed proximally toward the cardiacseptum on opposing sides of the septal defect. In one embodiment, theneedle holders are mounted on opposing sides of a balloon which may bedeflated during introduction through a septal defect and then inflatedto move the needles into the expanded position. The needle holders arethen pulled proximally so that the needles penetrate the cardiac septum.A means is mounted to the delivery shaft for capturing the distal tipsof the needles after penetrating the septum. For example, the needlesmay have barbed tips which engage a porous fabric disk slidably mountedto the delivery shaft. The needle capture means is retracted to draw theneedles through the septum and out of the heart through the inner lumenof the access device. In this way, a plurality of sutures may be appliedto the cardiac septum simultaneously. Knots may then be tied in thesutures extracorporeally, and, using a long-handled endoscopicknot-pusher, pushed through the access device into the heart so as totighten the sutures and draw the opposing sides of the septal defecttogether.

In a further aspect of the invention, a method of accessing an interiorchamber of a beating heart is provided. According to the method of theinvention, a penetration is formed in a muscular wall of the heart intoan interior chamber of the heart, and a distal end of a tubular accessdevice having an inner lumen is positioned through the penetration. Thepenetration may be formed with various types of endoscopic cuttingdevices, but, in a preferred embodiment, is formed with the cuttingmeans at the distal end of the obturator, which is positioned in theinner lumen of the access device. This allows the access device to beintroduced immediately upon forming the penetration, minimizing bloodloss through the penetration. The method further includes the step offorming a hemostasis seal between the access device and the penetrationto inhibit blood loss through the penetration. This step may includeplacing a purse string suture in the wall of the heart around thepenetration, inflating a balloon mounted to the access device within thechamber of the heart, or radially-expanding a portion of the accessdevice within the penetration.

The method also includes preventing blood flow out of the chamber of theheart through the inner lumen of the access device. This may beaccomplished by positioning the access device in a vertical orientationso that the pressure head of blood in the inner lumen is sufficient toprevent blood flow out of the heart, or a hemostasis valve may beprovided in the inner lumen.

While the method of accessing an interior chamber of the heart may finduse in openchest surgical procedures, it is preferably performed usingthoracoscopic techniques, wherein the ribs and sternum remain intact andare not significantly retracted during each step of the procedure. Usingsuch techniques, a working space may be created in the patient's chestcavity by collapsing one of the patient's lungs or using jet ventilationtechniques. A viewing scope such as an endoscope or endoscopic surgicalmicroscope may then be introduced through an intercostal space into theworking space to view the exterior of the heart while the penetration isformed and the access device is introduced. The viewing scope mayinclude a video camera to provide a video image of the heart for displayon a monitor which can be viewed during the procedure. Alternatively,the heart may be viewed directly through a lens on the viewing scope orthrough a trocar sleeve positioned in an intercostal space.

The method of accessing an interior chamber of the heart facilitates theperformance of a variety of intracardiac diagnostic and treatmentprocedures. While it may be desirable to place the patient oncardiopulmonary bypass and arrest the heart during certain procedures,the invention facilitates the performance of a number of cardiacprocedures while the heart is beating, without the need forcardiopulmonary bypass or cardioplegic arrest, and with significantlyreduced risk of injury resulting from embolism.

In a further aspect of the invention, a method is provided for closing acardiac septal defect in a patient's heart. The patient is first placedunder general anesthesia. The method is initiated by positioning thedistal end of the tubular access device in an interior chamber of theheart and creating a hemostatic seal around the access device, asdescribed above. These steps are preferably performed undervisualization by means of an endoscope or other percutaneousvisualization device. One or more instruments are then passed throughthe inner lumen of the access device and out of the distal end thereof.The one or more instruments are then used to close the septal defect.

In a preferred embodiment, the method of the invention is performedwhile the patient's ribs and sternum remain intact and unretracted, andwhile the patient's heart is beating. Access into the chest cavity isobtained through small percutaneous incisions or punctures in theintercostal spaces between the ribs. Trocar sleeves, ports, or othertypes of percutaneous access cannulae may be placed in these incisionsor punctures to protect and retract surrounding tissue to facilitateintroduction of instruments into the chest cavity.

Usually, the interior chamber of the heart will be the right atrium,right ventricle, or left atrium, in which blood pressure is lower thanin the left ventricle. Preferably, the access device is positioned in avertical orientation, usually from a lateral side of the chest, with thedistal end of the access device disposed in the interior chamber. Inthis way, the static pressure head of blood within the inner lumen isequal to the pressure within the interior chamber, preventing the flowof blood out of the interior chamber through the inner lumen. In anexemplary embodiment, small incisions and/or access ports are placed inthe third, fourth, fifth, or sixth intercostal spaces on a lateral sideof the chest. At least three such ports are usually required, one forintroduction of the access device, one for introduction of avisualization device such as an endoscope, and one for introduction ofother instruments for suturing, retraction, and other purposes.

Visualization within the interior of the heart may be provided byvarious means. Preferably, an ultrasonic probe is positioned in thepatient's esophagus, on the surface of the patient's chest, or in thechest cavity adjacent or in contact with the exterior of the heart toultrasonically image the interior of the heart. Alternatively, anendoscope with a translucent bulb or balloon over its distal end may beintroduced into the heart through the access device or through aseparate incision in the wall of the heart to allow video-based ordirect visualization of the interior of the heart. An angioscopeintroduced into the heart endovascularly through a peripheral vessel mayalso be used for intracardiac visualization. Fluoroscopy is anadditional technique for visualization.

The septal defect may be repaired in any of several ways. A patch may beattached to the cardiac septum to cover the defect, or the defect may besutured closed. As described above, the patch may be an artificialbiocompatible material, or it may be created out of a portion of thepatient's pericardium or other natural membrane in the patient's body.The patch is introduced through the inner lumen of the access device bymeans of a rigid delivery shaft to which the patch is detachablycoupled, allowing the patch to be positioned with a high degree ofcontrol and precision. The patch is inserted through the septal defectinto the left side of the heart in a collapsed configuration, and thenexpanded to cover the defect. When the patch has been positioned acrossthe defect, the interior of the heart is visualized by ultrasonicimaging, fluoroscopy with contrast dye injection, or other means todetermine whether the defect has been closed adequately. If not, thepatch may be retrieved and repositioned with the delivery shaft. Oncepositioned properly, the patch is anchored to the cardiac septum,preferably by the compressive force of an opposing patch, frame orseries of struts disposed on the right side of the septum. A number ofpins or spikes may be provided on the patch to partially penetrate theseptum to prevent migration. The patch is then released from thedelivery shaft.

In those embodiments in which the patch comprises a portion of thepericardium or other natural membrane, the invention allows the portionof membrane to be harvested from the patient's body and then affixed toa frame outside of the body cavity. Preferably, the membrane isharvested using instruments introduced percutaneously throughintercostal spaces, while keeping the ribs and sternum intact. Themembrane may be affixed to the frame using sutures, tissue adhesive,staples, or the like. Once the membrane is attached to the frame, thetwo may be coupled to the delivery shaft and introduced through theinner lumen of the access device into the heart for attachment to thecardiac septum.

Where the septal defect is to be closed by means of sutures, at leasttwo needles connected by a length of suture are introduced through theaccess device and inserted through the defect while the needles are in aradially retracted position. The needles are held in needle holderscoupled to the end of a delivery shaft. After insertion through thedefect, the needles are repositioned into a radially expanded positionin which they are further separated from one another. A balloon,expandable wire basket, scissors-type linkage, or camming device may beused for this purpose, or the needles may be held in needle holding rodshaving a shape memory so as to assume the radially expandedconfiguration when unrestrained. The needles are then drawn through thecardiac septum while in the expanded position. The needles are captured,and both ends of the length of suture are then tensioned to close thedefect. Usually the length of suture is long enough to allow the sutureneedles to be drawn outside of the body cavity through the inner lumenof the access device. Knots are then formed extracorporeally and pushedthrough the access device up to the cardiac septum using an endoscopicknot pusher. The sutures are trimmed using endoscopic scissors, and therepair is examined using one of the aforementioned visualizationtechniques.

Once the septal defect has been closed, the access device is withdrawnfrom the penetration in the wall of the heart. If a balloon or aradially expanding portion of the access device has been utilized forhemostasis, it is first deflated or radially contracted. As the distalend of the access device is withdrawn, the purse string suture in theheart wall surrounding the access device is pulled tight, closing thepenetration. Knots are then formed in the purse string suture, eitherintracorporeally using endoscopic instruments, or extracorporeally,after which the knots are pushed into the body cavity and against theheart wall using an endoscopic knot pusher. Alternatively, thepenetration in the heart wall may be closed using endoscopic suturing orstapling techniques after the access device has been withdrawn. Allaccess ports are then withdrawn, percutaneous incisions and puncturesare closed, and the patient is recovered from anesthesia.

In a further aspect of the invention, devices and methods are providedfor performing electrophysiological procedures within the heart. Suchprocedures include electrophysiological cardiac mapping and ablativetreatment of cardiac arrhythmias, including ventricular andsupraventricular tachycardias and atrial fibrillation. The inventionprovides devices and methods for diagnosis and treatment of suchdiseases by accessing the interior of the heart through the intracardiacaccess device described above. Such techniques avoid the need for agross thoracotomy, and offer more control and precision in diagnosingand treating these diseases than are offered by intravascularelectrophysiological treatment techniques.

An electrophysiological device according to the invention comprises arigid shaft suitable for introduction through the inner lumen of theaccess device. A deflectable tip is attached to the distal end of theshaft. The deflectable tip has at least one and usually a plurality ofelectrodes mounted to it. A steering means is provided in the shaft fordeflecting the tip into the desired orientation. The electrodes areelectrically coupled to a connector at the proximal end of the shaft,which may be connected to a sensitive electrocardiogram (ECG) monitoringapparatus or a radiofrequency generator?. The deflectable tip may beintroduced into a chamber of the heart through the access device, andthe electrodes positioned against a site on an interior wall of theheart to perform an electrophysiological procedure. For example, aplurality of electrode bands may be mounted in a spaced-apartrelationship on the deflectable tip, and the voltage difference can bemeasured across selected electrodes to identify aberrant conductionpathways in the heart wall, a process known as cardiac mapping. Inaddition, radiofrequency current may be delivered through one or moreelectrodes to ablate tissue at selected sites on the heart wall.

In a second embodiment, an electrophysiological device according to theinvention comprises an expandable electrode array mounted to the distalend of the rigid shaft. The electrode array includes a plurality ofelectrodes mounted to an expandable support structure such as a frame,basket, balloon, or series of rods. The support structure is coupled toan actuator at the proximal end of the shaft to facilitate selectivedeployment of the electrode array from a contracted configuration, inwhich it may be introduced through inner lumen of the access device, toan expanded configuration, in which the electrodes are spread apart intoa two-dimensional or three-dimensional array. In one embodiment, theelectrode array is configured to conform generally to the shape of aninterior chamber of the heart in the expanded configuration. In thisway, the electrodes may be positioned in a pattern along the interiorwalls of the heart chamber to facilitate mapping or ablation of a largearea without moving the device.

The electrophysiological devices of the invention are particularlyadvantageous in that they offer a high degree of control and precisionin positioning within the heart. Because the devices are manipulated bymeans of a rigid shaft that spans only the relatively short distancefrom the interior of the heart to the exterior of the chest cavity, theelectrodes can be easily and precisely positioned at most locationswithin the heart chamber. Moreover, because the electrophysiologicaldevices are not introduced endovascularly, they are not limited in sizeand configuration by blood vessel size. The devices may therefore haveelectrodes which are larger than those of endovascular electrophysiologydevices, permitting the delivery of greater amounts of energy to atissue site. Further, the electrodes may be greater in number and spreadout over a larger area than endovascular electrophysiology devices,allowing a greater area of a heart chamber to be mapped or ablatedwithout moving the device, thus increasing the precision and efficiencyof the procedure.

In a method of electrophysiological intervention according to theinvention, the tubular access device is introduced into a chamber of theheart in the manner described above. An electrophysiology deviceincluding at least one electrode coupled to the distal end of a shaft isintroduced through the tubular access device into the heart chamber. Theelectrode is positioned at a tissue site on a wall of the heart chamber,and either radiofrequency current is delivered to the tissue sitethrough the electrode, or electrical potential is sensed between two ormore selected electrodes. This technique may be used for either cardiacmapping or ablation of tissue. The method may further include deflectinga flexible tip attached to the shaft so that the electrode is positionedaway from a longitudinal axis of the shaft, permitting the electrode tobe positioned at various locations within the heart chamber.Alternatively, the method may include a step of expanding an electrodearray into an expanded configuration within the heart chamber. In theexpanded configuration, a plurality of electrodes of the electrode arrayare positioned in a two or three dimensional array which may bepositioned adjacent a treatment area on an interior wall of the heartchamber. Electrical potentials in the heart wall tissue may then besensed between selected electrodes, or radiofrequency current may bedelivered to the treatment area through one or more electrodes of theelectrode array.

The method may be performed in either the right side or the left side ofthe heart, and in either the atria or the ventricles. In ventricularprocedures, because it may be undesirable to form a penetration in thewall of a ventricle, the electrophysiology device may be introducedthrough the access device into an atrium, from which it is advancedthrough the tricuspid valve or mitral valve into the ventricle.Alternatively, the electrophysiology device may be positionedtranseptally through a puncture in the cardiac septum, wherein, afterelectrophysiological treatment is complete, the device is withdrawn andthe septal puncture closed.

The devices and methods of the invention may also be useful incombination with other types of cardiac treatment procedures. Forexample, the electrophysiology devices of the invention may be usefulfor mapping conduction pathways in the heart, which are then treated bymeans of thoracoscopic, endovascular, or open-chest techniques.Alternatively, thoracoscopic or endovascular techniques may be used formapping, and the intracardiac electrophysiological devices of theinvention may then be used for ablation or other treatments. In oneexemplary procedure, a thoracoscopic mapping device is introducedthrough an intercostal port in the chest for mapping cardiac conductionpathways on the exterior surface of the heart. The intracardiacelectrophysiology device of the invention is then utilized in theinterior of the heart to perform ablation, utilizing the mappinginformation generated on the exterior of the heart. Such a techniquecould be used for treatment of ventricular and supraventriculartachycardias. Similarly, to treat atrial fibrillation, intracardiacmapping may be performed using the electrophysiology device of theinvention, and thoracoscopic or endovascular cutting or ablationinstruments may then be utilized through intercostal ports to perform aCox "maze"-type surgical transection of the atrium, whereby the mappinginformation is used to make precise incisions or ablation lines in themyocardium to create a directed conduction pathway between thesinoatrial node and the atrioventricular node.

By providing access to the interior of the heart without requiring agross thoracotomy and without the need to induce cardioplegic arrest,the invention enables a variety of intracardiac procedures to beperformed on a beating heart. In addition to septal defect repair andthe electrophysiological procedures described above, these proceduresmay include repair of other types of congenital defects, transmyocardiallaser revascularization, mitral, aortic, pulmonary, or tricuspid valveinspection and repair, pulmonary thrombectomy, intracardiac inspection,removal of growths, myxomas, neoplasms, hypertrophic obstructivecardiopmyopathy and vegetations, and other diagnostic and treatmentprocedures.

The nature and advantages of the invention will become more apparentfrom the following detailed description of the invention when taken inconjunction with the accompanying exemplary drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a perspective view of an intracardiac access device accordingto the invention.

FIG. 2 is a front partial cut-away view of a patient's heart showing theintracardiac access device positioned through a wall thereof.

FIGS. 2A-2E are side views of a distal portion of the intracardiacaccess device of FIG. 1 showing various alternative types of sealingmeans.

FIGS. 3A-3C are side, top, and end views, respectively, of the obturatorof an intracardiac access device according to the invention with thecutting means retracted.

FIGS. 3D-3F are side, top, and end views, respectively, of the obturatorof an intracardiac access device according to the invention with thecutting means extended.

FIG. 4 is a front cut-away view of a patient's chest showing cutting thepericardium to expose the heart according to the method of theinvention.

FIG. 5 is a front cut-away view of a patient's chest showing theplacement of a pursestring suture in a muscular wall of the heartaccording to the method of the invention.

FIG. 6 is a front cut-away view of a patient's chest showing thepenetration of the muscular wall of the heart according the method ofthe invention.

FIG. 7 is a front cut-away view of a patient's chest showing theposition of the access device of FIG. 1 through the penetration in themuscular wall of the heart according to the method of the invention.

FIG. 8A is a front cut-away view of a patient's chest showing theposition of the access device of FIG. 1 through the penetration in themuscular wall of the heart with a balloon-type sealing means expandedaccording to the method of the invention.

FIG. 8B is a front cut-away view of a patient's chest showing the use ofan endoscope having a balloon over its distal end in a method ofvisualizing the interior of the heart according to the invention.

FIG. 9 is a front cut-away view of a patient's chest showing thedeployment of a distal patch of a septal defect repair device in achamber of the heart according to the method of the invention.

FIG. 10 is a side elevational view of a partially-deployed distal patchof a septal defect repair device useful in the method of the invention.

FIGS. 11A-11B are side cross-sectional and end views, respectively, of ahub of the distal patch of FIG. 10.

FIG. 12 is a side elevational view of a proximal patch of a septaldefect repair device useful in the method of the invention.

FIGS. 13A-13B are side cross-sectional and end views, respectively, of ahub of the proximal patch of FIG. 12.

FIG. 14 is a side cross-sectional view of the septal defect repairdevice of FIGS. 10-13 positioned in a lumen of a delivery shaftaccording to the method of the invention.

FIG. 15 is a front cut-away view of a patient's chest showing theexpansion of the distal patch of FIG. 10 in the left side of the heartaccording to the method of the invention.

FIG. 16 is a front cut-away view of a patient's chest showing thedeployment of the proximal patch of FIG. 12 in the right side of theheart according to the method of the invention.

FIG. 17 is a front cut-away view of a patient's chest showing theexpansion of the proximal patch of FIG. 12 in the right side of theheart according to the method of the invention.

FIG. 18 is a front cut-away view of a patient's chest showing theattachment of the proximal patch to the distal patch to repair theseptal defect according to the method of the invention.

FIG. 19 is a front cut-away view of a patient's chest showing theclosure of the penetration in the muscular wall of the heart accordingto the method of the invention.

FIG. 20 is a transverse cross-sectional view of the patient's chestshowing an alternative technique for closing the penetration in themuscular wall of the heart according to the method of the invention.

FIG. 21A, 22A, and 23 are top partial cut-away views of alternativeembodiments of a septal defect repair device according to the principlesof the invention.

FIGS. 21B and 22B are side cross-sectional views of the septal defectrepair devices of FIGS. 21A and 22A, respectively.

FIG. 24A is a top partial cut-away view of a further embodiment of aseptal defect repair device according to the principles of theinvention.

FIG. 24B is a side partial cut-away view of the septal defect repairdevice of FIG. 24A.

FIG. 25A is a side cut-away view of the septal defect repair device ofFIGS. 24A-24B positioned in a collapsed configuration within a deliveryshaft.

FIG. 25B is a side cut-away view of an actuator handle for deployment ofthe septal defect repair device of FIGS. 24-24B.

FIGS. 26A-26B is a side cross-sectional view showing the attachment ofthe septal defect repair device of FIGS. 24A-24B to a cardiac septumaccording to the method of the invention.

FIGS. 27 is a front cut-away view of a patient's chest showing theintroduction of a suturing device into the heart for repairing a septaldefect in an alternative embodiment of the method of the invention.

FIG. 28 is a front cut-away view of a patient's chest showing theexpansion of a plurality of needles at the distal end of the suturingdevice according to the method of the invention.

FIG. 29A is a front cut-away view of a patient's chest showing drawingthe plurality of needles through the cardiac septum according to themethod of the invention.

FIG. 29B is a side view of the cardiac septum in the patient's chest ofFIG. 29A showing the position of the needles through the cardiac septumaccording to the method of the invention.

FIG. 30A is a side view of the cardiac septum of FIG. 29B showingcapturing the needles in a capture disk according to the method of theinvention.

FIG. 30B is a side view of the cardiac septum of FIG. 30A showingwithdrawing the needles from the cardiac septum according to the methodof the invention.

FIG. 31A is a top view of the cardiac septum of FIG. 30A showing theposition of the sutures across the septal defect according to the methodof the invention.

FIGS. 31B-31C are perspective views of the cardiac septum of FIG. 31Ashowing tensioning and tying the sutures to close the septal defectaccording to the method of the invention.

FIGS. 32A-32D are side views of an alternative embodiment of asuture-type septal defect repair device according to the invention,showing the deployment of the needles in the cardiac septum and thecapture of the needles according to the method of the invention.

FIG. 33 is a front cut-away view of a patient's chest showing anelectrophysiology device according to the invention positioned throughthe access device of FIG. 1 in a method of electrophysiologicaltreatment according to the invention.

FIG. 34 is a front cut-away view of a patient's chest showing analternative embodiment of an electrophysiology device according to theinvention positioned through the access device of FIG. 1 in a method ofelectrophysiological treatment according to the invention.

DETAILED DESCRIPTION OF SPECIFIC EMBODIMENTS

A first representative embodiment of an intracardiac access systemaccording to the invention is illustrated in FIG. 1. The intracardiacaccess system 20 includes a tubular access device 22 comprising a rigidshaft 24 having a distal end 26, a proximal end 28, and an inner lumen30 extending therebetween. Access device 22 includes a means near distalend 26 for hemostatically sealing a cardiac penetration through whichshaft 24 is introduced, which may comprise a toroidal balloon 32. Aninflation lumen 34 extends through shaft 24 and has an opening 36 incommunication with the interior of balloon 32. An inflation fluid port38 is mounted to shaft 24 at proximal end 28 in communication withinflation lumen 34 and is configured for connection to an inflationfluid delivery source such as a syringe or other balloon inflationdevice.

Access device 22 is configured to extend percutaneously through anintercostal space and through a muscular wall of the heart with distalend 26 positioned in an interior chamber of the heart and proximal end28 positioned outside of the patient's chest cavity. In an exemplaryembodiment, the tubular access device has a length of about 10 to 30 cm,preferably about 25 cm, and an outer diameter of less than about 15 mm,and preferably about 5-10 mm. To allow introduction of instruments forvisualization and surgical intervention within the heart, inner lumen 30has a diameter of at least about 5 mm. Preferably, access device 22 is arigid material such as stainless steel, titanium, or a rigid polymer,with a minimum durometer of about 75 Shore A. Alternatively, shaft 24 ofaccess device 22 may be all or partially flexible with a minimumdurometer of about 35 Shore A, and may also include pull wires or othermeans for steering or deflecting distal end 26.

As illustrated in FIG. 2, distal end 26 of access device 22 isconfigured to be introduced through a penetration in cardiac wall 40 ofheart H. The hemostatic sealing means, e.g. balloon 32, functions toseal the penetration around the exterior of shaft 24 to prevent leakageof blood through the penetration from the interior of heart H. Asillustrated in FIGS. 2A-2E, a variety of hemostatic sealing means may beutilized. Balloon 32 may be mounted to shaft 24 spaced a short distancefrom distal end 26 so as to be positionable against the exterior surfaceof cardiac wall 40, as shown in FIG. 2A. Balloon 32 may alternatively bemounted close to distal end 26 so as to be positionable against theinterior surface of cardiac wall 40 as shown in FIG. 2B. In addition, apair of balloons 32, 42 may be mounted to shaft 24 spaced slightly apartto provide a seal on both sides of cardiac wall 40, as shown in FIG. 2C.

In a further alternative embodiment, not pictured, either or both ofballoons 32, 42 of FIG. 2C may be replaced by expanding mechanicalelements, such as moly-type fittings which are expanded undercompression exerted by, for example, sliding a slidable sleeve axiallyover shaft 24 which engages the proximal ends of the fittings.

In a further embodiment, shown in FIG. 2D, shaft 24 may have a flange 44disposed at distal end 26, flange 44 having a proximal end 46 with anouter diameter larger than that of shaft 24. When flange 44 isintroduced through a cardiac penetration, proximal end 46 of flange 44may be positioned so as to abut and seal against the interior surface ofcardiac wall 40. Flange 44 preferably has tapered side walls 48 tofacilitate introduction through the cardiac penetration. As shown inFIG. 2, balloon 32 may be mounted to shaft 24 spaced proximal to flange44 to compress cardiac wall 40 between the balloon and the flange andseal the cardiac penetration both interiorly and exteriorly.

In another embodiment, illustrated in FIG. 2E, shaft 24 has aradially-expanding portion 50 near distal end 26 which may beselectively expanded when distal end 26 has been positioned through thecardiac penetration. Exemplary radially-expanding dilators and cannulaehaving a construction suitable for application to the present inventionare disclosed in U.S. Pat. Nos. 5,183,464 and 4,921,479, which areincorporated herein by reference. A balloon 32 may also be mounted toshaft 24 distally of radially-expanding portion 50 to seal against theinterior surface of cardiac wall 40.

In each of the forementioned embodiments, it will frequently beadvantageous to place a purse string suture in cardiac wall 40 or applyanother means of gathering tissue around the cardiac penetration throughwhich shaft 24 is introduced to enhance hemostasis. The placement ofsuch a purse-string suture is described in detail below.

Referring now to FIGS. 3A-3C and 3D-3F, cardiac access system 20 furtherincludes an obturator 52 removably positionable in inner lumen 30.Obturator 52 comprises a tubular shaft 54 having a distal end 56, aproximal end 58, and an axial lumen 59. Distal end 56 is conical inshape and has a transverse slot 57 in communication with axial lumen 59.A cutting means 60 for forming a penetration in a heart wall is slidablyreceived within slot 57, and, in an exemplary embodiment, comprises astainless steel blade 62 having a sharpened distal edge 64 tapering to apoint 66. Blade 62 is coupled to a linkage 72 slidably disposed in axiallumen 59. A handle 74 is mounted to proximal end 58 of shaft 54, and asliding actuator 76 is mounted to handle 74. Linkage 72 is coupled toactuator 76, so that actuator 76 may be used to slide blade 62 distallyto expose edge 64 and point 66. A compression spring 78 is disposedwithin an aperture in handle 74 and engages a collar 79 on linkage 72 tobias blade 62 proximally so that it is protected within slot 57.

Actuator 76 may be configured to lock in a distal position in whichblade 62 is fully exposed, in a proximal position in which blade 62 isfully exposed, or in any other position between the two. In an exemplaryconfiguration, actuator 76 comprises a button 77 having an upper portion81 of smaller diameter which is slidable within a channel 80 in handle74, and having a lower portion 82 of larger diameter designed to seatwithin a detent 84 at the proximal end of channel 80. Button 77 isbiased upward by a spring 85 to automatically lock into detent 84 whenaligned therewith. In this way, blade 62 is locked in the proximalposition and is unlikely to be inadvertently exposed by the user. Whenexposure of blade 62 is desired, button 77 is pushed downward anddistally. Release of pressure on button 77 causes blade 62 to retractautomatically.

The length of shaft 54 is selected so that when obturator 52 is disposedwithin inner lumen 30, cutting means 60 extends distally of distal end26 of access device 22 and handle 74 is near or against proximal end 28of access device 22. In this way, blade 62 may be used to create apenetration in the heart wall while obturator 52 is positioned withinaccess device 22, allowing access device 22 to be introduced through theheart wall as or immediately after the penetration is formed, therebyminimizing blood loss through the penetration. Once access device 22 isintroduced through the cardiac penetration, obturator 52 is withdrawnfrom inner lumen 30.

As will be described more fully below, access device 22 is usuallyintroduced into the right atrium, right ventricle, or left atrium in avertical or near-vertical orientation so that blood flow out of theheart through inner lumen 30 is prevented by gravity--i.e., the pressurehead of blood in inner lumen 30 is equal to that in the cardiac chamber.In such cases, there is no need for a hemostasis valve within innerlumen 30. However, in cases in which access device 22 is to beintroduced into the higher pressure chamber such as the left ventricle,or in which access device 22 is to be positioned in an orientation inwhich blood might flow through inner lumen 30, a hemostasis valve (notshown) may be provided within inner lumen 30. The hemostasis valve maybe positioned at the proximal end, the distal end, or a mid-positionwithin inner lumen 30, and will be configured to allow instruments to beintroduced through inner lumen 30 with minimal blood loss. Suitablehemostasis valves are described, for example, in U.S. Pat. Nos.4,000,739, 4,436,519, 5,154,701, 4,946,133, 5,000,745, 4,177,814, and5,300,033, which are incorporated herein by reference.

A method of accessing the interior of the heart according to theinvention will now be described with reference to FIGS. 4-8. The methodwill be described in relation to accessing a left or right atrium of theheart from the right side of the chest, but it should be understood thatthe principles described will be equally applicable to accessing theleft or right ventricle and using any of a variety of approaches.

The patient is prepared for cardiac surgery in the conventional manner,and general anesthesia is induced. The patient is positioned on thepatient's left side so that the right lateral side of the chest isdisposed upward. Two to three small incisions 2-3 cm in length are madebetween the ribs, usually in the third, fourth, or fifth intercostalspaces. Thoracoscopic access ports 90 (e.g. trocar sleeves or othertubular cannulae), are positioned in each incision to retract awayadjacent tissue and protect it from trauma as instruments are introducedinto the chest cavity. Access ports 90 have an outer diameter which doesnot require retraction, cutting or removal of ribs, preferably less than14 mm, and an axial passage with a diameter less than about 12 mm.Access ports 90 may also be non-circular in cross-section, or may bemade of a flexible material to deform into a non-circular shape whenintroduced between two ribs. The right lung is deflated usingconventional techniques, usually by introducing a tube through thepatient's trachea into the right lung and applying a vacuum through thetube to deflate the lung. An endoscopic visualization device such as athoracoscope 92 connected to a video monitor (not shown) by a cable 93is introduced through one of access ports 90 to visualize the interiorof the chest cavity. Atraumatic retraction instruments may be introducedthrough access ports 90 to assist in deflating and retracting the lung,thereby providing a working space within the chest cavity.

Referring to FIG. 4, in order to gain access to the heart, an opening ismade in the pericardium 94 using thoracoscopic instruments introducedthrough access ports 90, including thoracoscopic scissors 96 andthoracoscopic forceps 98. Instruments suitable for use in this procedureare described in copending application Ser. No. 08/194,946, filed Feb.11, 1994, now U.S. Pat. No. 5,501,698, which is incorporated herein byreference. An opening approximately 2 cm-8 cm square is formed in thepericardium, exposing the exterior of the heart 100.

As shown in FIG. 5, a purse string suture 102 is then placed in the wall104 of heart 100 around the site at which it is desired to introduceaccess device 22. This is accomplished by using thoracoscopic needledrivers 106 to introduce into the chest cavity a curved suture needle108 attached to one end of a suture thread 110, and to drive the needlethrough the heart wall to form a running stitch in a circular patternapproximately 12-14 mm in diameter. A double-armed suture may also beused, wherein the suture thread 110 has needles at both ends, allowingeach needle to be used to form one semi-circular portion of thepurse-string. Suture thread 110 may be long enough to allow both ends ofthe suture to be drawn outside of the chest cavity once purse-stringsuture 102 has been placed, or it may be shorter and manipulated withinthe chest cavity using thoracoscopic instruments. Suture needle 108 isthen cut from thread 110 using thoracoscopic scissors.

Access device 22 may now be introduced into heart 100. In some cases, itmay be advantageous to first place the patient on cardiopulmonary bypassand to place the heart under cardioplegic arrest before introducingaccess device 22. Preferably, however, heart 100 remains beating duringthe procedure to avoid the trauma and risks associated with cardioplegicarrest. Obturator 52 is positioned within inner lumen 30 of accessdevice 22 so that distal end 56 of the obturator is exposed distally ofdistal end 26 of the access device. Access device 22 with obturator 52positioned therein is introduced through an access port 90 into thechest cavity, and distal end 56 of the obturator is positioned againstheart wall 104 centrally within the bounds of purse-string suture 102.Button 77 on handle 94 of the obturator is then pressed downward anddistally so as to extend blade 62 from distal end 56, causing blade 62to penetrate through heart wall 104. A thoracoscopic grasping instrument(not shown) may be used to grasp the heart wall near purse string suture102 to counter the insertion force of blade 62 and access device 22. Asblade 62 penetrates the heart wall, access device 22 is advanceddistally in conjunction with obturator 52 so that both devices extendinto the heart through the penetration 114 formed in heart wall 104.

Once distal end 26 of access device 22, including balloon 32 or flange44 if used, is within the interior of heart 100, purse-string suture 102is cinched tightly to form a hemostatic seal around access device 22, asshown in FIG. 7. One or a pair of thoracoscopic cinching devices 116 maybe used for this purpose. Each cinching device 116 comprises a shaft 118with a slidable hook 120 at its distal end which can be used to grasp aloop of purse-string suture 102. Hook 120 may retracted proximally tofrictionally retain suture thread 110 against the distal end of shaft118. Loops on opposing sides of purse-string suture 102 may be graspedin this manner, and cinching devices 116 then withdrawn proximally tocinch purse-string suture 102 tightly, thereby gathering heart walltissue against the exterior of access cannula 22 to form a hemostaticseal. Cinching devices 116 may be clamped in position to maintaintension on suture thread 110. Alternatively, a slidable sleeve 122 maybe provided around shaft 118. Once a suture loop has been secured inhook 120, slidable sleeve 122 may be slid distally relative to shaft 118until it abuts against the surface of heart wall 104. Shaft 118 is thenpulled proximally relative to sleeve 122 to obtain the desired degree oftension on suture thread 110. Sleeve 122 is configured to frictionallyretain shaft 118 in position to maintain tension on the suture.

If a balloon or radially-expanding portion of access device 22 is usedto enhance hemostasis, it is now activated. The use of a balloon 32,described above in reference to FIG. 2B, is illustrated in FIG. 8A. Oncedistal end 26 of access device 22 is introduced into the interior ofheart 100, balloon 32 is inflated by introducing an inflation fluid suchas saline through inflation lumen 34 (FIG. 1). A syringe or othercommercially-available inflation device connected to inflation port 38may be used for this purpose.

Obturator 52 is then withdrawn from inner lumen 30 of access device 22.As described above, access device 22 is preferably positioned in avertical orientation so that outflow of blood from the heart throughinner lumen 30 is prevented by gravity--that is, the pressure head ofblood within inner lumen 30 is equal to that in the cardiac chamber. Inother cases, a hemostasis valve (not shown) is provided within innerlumen 30 to prevent blood flow from the heart, while allowinginstruments to be introduced through the access device.

The patient has now been prepared for a diagnostic or treatmentprocedure to be carried out within heart 100 through access device 22.Advantageously, the need for gross thoracotomy, cardiopulmonary bypassand cardioplegic arrest have been avoided, while providing a relativelylarge, straight, and hemostatically-sealed access passage directly intothe interior of the heart.

Visualization within the heart may be accomplished in any of severalways. Transesophageal echocardiography may be used, wherein anultrasonic probe is placed in the patient's esophagus or stomach toultrasonically image the interior of the heart. An ultrasonic probe mayalso be placed through one of access ports 90 into the chest cavity andadjacent the exterior of the heart for ultrasonically imaging theinterior of the heart.

Alternatively, as illustrated in FIG. 8B, an endoscope 121 having anoptically transparent bulb such as an inflatable balloon 123 over itsdistal end 125 may be introduced through access device 22 into theinterior of the heart. Balloon 123 may be inflated with a transparentinflation fluid such as saline to displace blood away from distal end125 and may be positioned against a site such as septal defect D inseptum S, allowing the location, shape, and size of defect D to bevisualized. In one embodiment, endoscope 121 is a conventional,commercially-available endoscope such as a V. Mueller Model No. LA 7005(V. Mueller, Inc, Deerfield, Ill.), having a tubular shaft 127 in whichone or more lenses (not shown) are mounted, an eyepiece 129 at itsproximal end for looking through tubular shaft 127, and a connector 131for connection to a light source which transmits light through opticalfibers (not shown) extending through tubular shaft 127 to distal end125. Endoscope 121 is slidably positioned in an outer sleeve 133 havinga distal end 135 to which balloon 123 is attached. Outer sleeve 133 hasa luer connection 137 on its proximal end in communication with aninflation lumen (not shown) extending through outer sleeve 133 to anoutlet port 139 at distal end 135 within the interior of balloon 123.Luer connection 137 is adapted for connection to a syringe 141 forinjecting a transparent inflation fluid such as saline into balloon 123for inflation thereof. A tubular, compliant seal 143 is attached to aproximal end of outer sleeve 133 to provide a fluid-tight seal betweenendoscope 121 and outer sleeve 133. It will be understood to those ofskill in the art that, instead of using separate outer sleeve 133,balloon 123 could be mounted directly to distal end 125 of endoscope 121and an inflation lumen provided in shaft 127 for inflation of theballoon.

In use, endoscope 121 is positioned in outer sleeve 133 outside of thepatient, and the two are together introduced through inner lumen 30 ofaccess device 22 with balloon 123 evacuated of fluid in a collapsedconfiguration. Once balloon 123 is within the heart, saline is injectedinto balloon 123 to inflate the balloon to a diameter of approximately2-6 cm. Balloon 123 is then positioned against the site to bevisualized, e.g., septum S around defect D. The size and location of thedefect D may then be visualized by looking through eyepiece 129.Additionally, endoscope 121 may include a video camera mount to allowvideo imaging and remote viewing of the interior of the heart on a videomonitor.

Instead of a balloon or bulb over distal end 125, saline may be injectedunder pressure through a lumen in endoscope 121 or in outer sleeve 133and out of a port at or near distal end 125 to displace blood away fromthe distal end to provide a transparent field of view.

As a further visualization alternative, an endoscope may be utilizedwhich employs a specialized light filter, so that only those wavelengthsof light not absorbed by blood are transmitted into the heart. Theendoscope utilizes a CCD chip designed to receive and react to suchlight wavelengths and transmit the image received to a video monitor. Inthis way, the endoscope can be positioned in the heart through accessdevice 22 and used to see through blood to observe a region of theheart. A visualization system based on such principles is described inU.S. Pat. No. 4,786,155, which is incorporated herein by reference.

In still another alternative for visualization, particularly useful inimaging an atrial or ventricular septal defect, a very small-profilelight source such as an optical fiber is positioned in the left atriumor left ventricle, opposite the right atrium or right ventricle in whichaccess device 22 is positioned. The light source may be introducedthrough access device 22 and through the septal defect into the leftside of the heart, or it may be introduced through a minute puncture inthe left side of the heart. The puncture may be closed by a purse-stringsuture if needed. An endoscope is then positioned through access device22 into the right side of the heart opposite the light source. Theendoscope utilizes a CCD chip designed to receive and react to thoselight wavelengths transmitted through blood, as well as any lightwavelengths transmitted through the interatrial or interventricularseptum. This produces a shadow-like image of the septal defect, which isreceived by the CCD and displayed on a video monitor, thereby imagingthe size, shape and location of the septal defect.

With access device 22 in position in the heart and a means ofvisualization in place, a number of intracardiac procedures may beperformed. One such procedure is the repair of atrial septal defects,which will now be described with reference to FIGS. 9-32.

FIGS. 9-20 illustrate an exemplary embodiment of a system and method forrepairing an atrial septal defect according to the invention. In theseFigures, an umbrella-type septal defect repair patch is shown which issimilar to that that described in U.S. Pat. No. 3,874,388 to King, whichis incorporated herein by reference. It should be understood, however,that any of a number of different septal defect repair patches may beutilized in conjunction with the system and method of the inventionwithout departing from the principles thereof. Some of the septal defectrepair patches which could be utilized are described, for example, inU.S. Pat. Nos. 4,007,743, 5,334,217, 4,917,089, 5,284,488, and5,108,420, which are incorporated herein by reference. Another septaldefect repair patch which could be used with the present invention isdisclosed in PCT application No. PCT/US92/10141 to Pavcnik, publishedJun. 10, 1993.

As shown in FIG. 9, the septal defect repair system of the inventionincludes, in addition to access device 22 described above, a defectrepair device 130 and a delivery means 132. Defect repair device 130comprises, in this embodiment, a double umbrella-type patch similar tothat described in the '388 patent to King. Delivery means 132 comprisesa tubular delivery shaft 134 having a distal end 136 positionablethrough inner lumen 30 of access device 22, and a proximal end (notillustrated in FIG. 9) which is used to manipulate delivery means 132from outside of the chest cavity. An outer tubular control rod 138 isslidably disposed within delivery shaft 134, and an inner control rod140 is slidably disposed within outer control rod 138. Inner control rod140 has a distal end 142 detachably coupled to a distal patch 144 ofdefect repair device 130.

Preferably, delivery shaft 134 is generally straight and rigid tofacilitate introduction through access device 22 and manipulation ofdelivery means 132 from its proximal end. Delivery shaft 134 is thusstainless steel, titanium, another biocompatible metal, or abiocompatible polymer with a minimum durometer of 75 Shore A. Outercontrol rod 138 and inner control rod 140 are preferably also a rigidmaterial such as stainless steel or titanium, although some flexibilitymay be tolerated in these members since they are supported exteriorly bydelivery shaft 134, so long as the inner and outer control rods havesufficient column strength to perform their respective functions, asdescribed below.

The details of an exemplary embodiment of defect repair device 130 areillustrated in FIGS. 11, 12A-12B, 13 and 14A-14B, which show adouble-umbrella device similar to that disclosed in the King patent.FIG. 11 illustrates distal patch 144, which includes a central hub 146to which a plurality, e.g. six, radially-extending struts 148 arecoupled. Hub 146 and struts 148 are a rigid material such as stainlesssteel or a biocompatible polymer. Struts 148 include sharpened points149 pointing generally perpendicular to the struts at their outer endsfor penetrating the cardiac septum. A biocompatible flexible fabric 150of a polyester such as Dacron™, an expanded polytetrafluoroethylene suchas Gore-Tex® (W. L. Gore and Assoc., Inc.), silk, nylon, silastic, aportion of the patient's pericardium, or other biocompatible flexiblematerial impervious to blood is attached to hub 146 by a keeper 152 andto struts 148 by sutures 154.

As shown in FIGS. 11A-11B, struts 148 may be hingedly coupled to hub 146by means of a hinge ring 156 which extends through an eyelet 158 at theend of each strut. Hinge ring 156 and struts 148 are retained on hub 146by keeper 152. Alternatively, struts 148 may be a resilient, flexiblematerial and rigidly coupled to hub 146 so as to naturally assume aradially expanded configuration when unrestrained. A plurality of axialgrooves 159 are provided on hub 146 to receive struts 148 when collapsedinward. Hub 146 further includes a threaded hole 160 on its proximal endinto which the threaded distal end of inner control rod 140 may bethreaded. A circumferential flange 162 is disposed about the proximalend of hub 146 for attachment to the proximal patch of the defect repairdevice, as described below.

Referring to FIGS. 12 and 13A-13B, defect repair device 130 furtherincludes a proximal patch 164 having a construction much like distalpatch 144. A plurality of struts 166 are hingedly coupled to a centralhub 168 by means of a hinge ring 170 extending through eyelets 172 inthe inner ends of the struts. Each strut 166 has an inwardly extendingpoint 174 at its outer end for engaging the cardiac septum. A flexiblefabric membrane 176 is attached to hub 168 by a keeper 180 and to struts166 by sutures 182. Additional suture loops 184 are attached to struts166 to allow attachment of tie wires for deployment of proximal patch164, as described below.

As shown in FIGS. 13A-13B, hub 168 has a plurality of axial grooves 186for receiving struts 166 in a collapsed configuration. Hub 168 also hasan axial passage 188 of sufficient diameter to allow inner control rod140 to extend slidably through it with minimal friction. On its distalend, hub 168 has a cavity 190 having an annular groove 192 for receivingcircumferential flange 162 of hub 146 in a snap-fit relationship.

Referring to FIG. 14, during introduction through access device 22,distal patch 144 and proximal patch 64 are preferably positioned in acollapsed configuration within delivery shaft 134 near distal end 136.Inner control rod 140 is positioned slidably through outer control rod138, through axial passage 188 in hub 168 of proximal patch 164, andthreaded into hole 160 in distal patch 144. Tie wires 194 are attachedto suture loops 184 and extend proximally through delivery shaft 134 outof the chest cavity. As shown in FIG. 9, delivery shaft 134 isintroduced through the right atrium RA and into the left atrium LAthrough septal defect D. Inner control rod 140 is then advanced distallyrelative to delivery shaft 134 to deploy distal patch 144 out ofdelivery shaft 134 into left atrium LA.

As illustrated in FIG. 15, with distal patch 144 deployed in the leftatrium, inner control rod 140 is pulled proximally relative to deliveryshaft 134 until distal end 136 of the delivery shaft engages struts 148(not shown in FIG. 15), urging struts 148 outward to a radially expandedposition in which distal patch 144 is generally disk-shaped and parallelto cardiac septum S. Delivery shaft 134 and control rod 140 are thenpulled proximally in the direction of arrow A1 until distal patch 144engages septum S and points 149 of struts 148 partially penetrate septumS. This is done under visualization by TEE or one of the othertechniques described above in order to ensure proper positioning ofdistal patch 144 so as to fully block blood flow across defect D. If,after initial placement, shunting of blood is detected across thedefect, distal patch 144 may be repositioned by advancing delivery shaft134 distally to disengage patch 144 from septum S, then manipulatingdelivery shaft 134 to position distal patch 144 in the desired location.The straightness, rigidity, and relatively short length of deliveryshaft 134 provide the user a high degree of control and precision inplacing the patch in the best possible position on septum S.

In some cases it may be desirable to have the capacity to re-collapsedistal patch 144 and replace it within delivery shaft 134 forrepositioning or removal from the patient. In such cases, tie wires maybe provided which are coupled to the inner sides of struts 148 andextend through delivery shaft 134 out of the chest cavity. By tensioningthe tie wires, struts 148 may be urged back into a collapsed positionand distal patch 144 then pulled back into delivery shaft 134.

With distal patch 144 anchored in septum S, proximal patch 164 is nextdeployed in the right atrium RA, as illustrated in FIG. 16. This isaccomplished by pulling delivery shaft 134 proximally to provide somespace between its distal end 136 and septum S. Outer control rod 138 isthen advanced distally relative to delivery shaft 134 to deploy proximalpatch 164 out of delivery shaft 134 in the direction of arrow A2.Proximal patch 164 and outer control rod 138 slide relative to innercontrol rod 140, which is maintained in tension to keep distal patch 144against septum S.

As shown in FIG. 17, tie wires 194 are then tensioned so as to urgestruts 166 outward into a radially expanded position in which proximalpatch 164 is generally disk-shaped and parallel to septum S. Asillustrated in FIG. 18, outer control rod 138 and proximal patch 164 arethen advanced distally over inner control rod 140 until hub 168 of theproximal patch engages and snaps into hub 146 of distal patch 144.Points 174 on the ends of struts 166 partially penetrate septum S toanchor the patch in position. Tie lines 194 are removed from proximalpatch 164, by, for example, cutting the tie lines with a cuttinginstrument introduced through access device 22 after removal of deliveryshaft 134. Alternatively, tie lines 194 may be looped through sutureloops 184 on proximal patch 164 so that both ends extend out of thechest cavity, in which case one end of each tie line is simply pulledthrough the suture loop to remove the tie line.

It will be understood to those of ordinary skill in the art that avariety of different types of actuators of well-known construction maybe employed at the proximal end of delivery means 132 to allow the userto selectively deploy defect repair device 130 in the heart. In oneembodiment, not pictured, a handle is fixed to the proximal end ofdelivery shaft 134 which is suitable for being grasped in the user'shand. A pair of slidable buttons are mounted to the handle, one beingcoupled to the proximal end of the inner control rod 140 and the secondbeing coupled to the proximal end of outer control rod 138. In this way,the user can independently deploy distal patch 144 and proximal patch164 by sliding the respective buttons on the handle. A passage is alsoprovided in the handle in communication with the interior of deliveryshaft 134 to allow tie wires 194 to extend out of the delivery shaftoutside of the patient's body.

Delivery shaft 134, along with inner control rod 140 and outer controlrod 138, are then removed from the chest cavity through access device22. If desired, the defect repair may be inspected by placing anendoscope with a transparent bulb or balloon over its distal end throughaccess device 22 into right atrium RA. The bulb or balloon is positionedagainst septum S and/or proximal patch 164 to inspect the position ofthe patch and to determine whether the septal defect has been completelyoccluded. Shunting of blood may also be detected using TEE or otherultrasonic technique. If patch position is satisfactory, access device22 may be removed from the patient. Balloon 32 (if used) is deflated,and access device 22 is withdrawn from the penetration in heart wall104. As shown in FIG. 19, sutures 110 are pulled tight as access device22 is withdrawn to close the penetration without significant loss ofblood from the heart. Knots are tied in sutures 110, usuallyextracorporeally, and slid into the chest cavity and against heart wall104 using an endoscopic knot pusher 196 introduced through access port90. This may be done under visualization with an endoscope introducedthrough a separate access port 90 (not shown in FIG. 19). Sutures 110are then trimmed off with a pair of endoscopic scissors.

An alternative method of closing the penetration in the heart wall isillustrated in FIG. 20. In this technique, an endoscopic staple applieris used to apply one or more staples to the heart wall across thepenetration. A staple applier such as, for example, an AutoSuture™Powered Multifire Endo TA60 device available from United States SurgicalCorp. of Norwalk, Conn., may be utilized. Under visualization using anendoscope positioned in an access port 90, stapler 198 is introducedthrough an access port 200 in the anterior wall of the patient's chestso that the anvils 202 are generally parallel to heart wall 104. Theheart wall around the penetration is pursed up using endoscopic forcepsso that anvils 202 can be positioned around a portion of the myocardiumthat includes the penetration. The stapler is then actuated, applying arow of staples through the heart wall across the penetration to seal itclosed.

With the penetration in heart wall 104 closed, the procedure iscompleted by removing all access ports 90 and closing all percutaneousincisions. The right lung is re-inflated, the endotracheal tube isremoved, and the patient is recovered from anesthesia.

Additional embodiments of defect repair device 130 of the invention areillustrated in FIGS. 21A-21B, 22A-22B, 23, and 24A-24B. Defect repairdevices 130A, 130B, 130C of FIGS. 21-23 each include a distal patch 206,208, 210, and a proximal patch 212, 214, 216. The patches are aflexible, biocompatible, and blood impervious material, preferablyconducive to endothelialization after implantation. Suitable materialsinclude polyester mesh, knit fabrics of expanded polytetrafluoroethylenetreated for low porosity, absorbable polyhydroxybutyrate, autologouspericardium, bovine or porcine pericardium, polyurethane andpolypropylene mesh. The proximal and distal patches are attachedtogether in a parallel relationship by an attachment means 218, 220, 222forming a ring at the center of the patches. Attachment means 218 maycomprise a single suture in a circular running stitch, a plurality ofindividual knotted suture loops, rivets, or other fasteners, or acircular series or continuous line of adhesive bonding or heat welding.A wire support frame 224, 226, 228 is attached around the outer edges ofthe distal and proximal patches, preferably by folding the outer edgesof the patch around the frame and suturing or bonding the patch toitself, thereby enclosing the support frame within the patch material.On each patch, support frame 224, 226, 228 is preferably a singlecontinuous wire of Nitinol™, a superelastic nickel-titanium alloyavailable from Raychem Corporation, titanium, or stainless steel.Support frame 224, 226, 228 includes a plurality of loops 230, 232, 234formed in the plane of each patch to allow for longitudinal flexing andbending of the frame to facilitate collapsing the patches duringintroduction. The loops may be formed outwardly to lie outside of theperiphery of each side of the frame as illustrated in FIG. 21A, orinwardly to lie within the periphery of the frame as illustrated inFIGS. 22 and 23.

In the embodiment of FIGS. 22A-22B, defect repair device 130B includes acentral hub 236 attached to distal and proximal patches 208, 214. Hub236 has a post 238 extending through patches 208, 214, and a retainer240 threaded or press-fit onto the distal end of post 238, therebyfixing hub 236 to the patches. Hub 236 also has a threaded hole 242 inits proximal end to which an introducer shaft may be threadably coupled.By allowing defect repair device 130 to be coupled to an introducershaft via hub 236, the user is given a higher degree of control inpositioning and repositioning the patch, as described more fully below.It should be understood that any of the embodiments in FIGS. 21A-21B and23 may be provided with a hub like hub 236 of FIG. 22.

Patches 212, 214, 216 may have any of a variety of shapes includingsquare or rectangular (FIGS. 21 and 22), hexagonal (FIG. 23),triangular, octagonal, pentagonal, circular, oval, or other shape. Adefect repair device like those disclosed in U.S. Pat. No. 5,334,217 toDas, which is incorporated herein by reference, may also be utilized inconjunction with the present invention.

FIGS. 24A-24B illustrate still another embodiment of defect repairdevice 130. In this embodiment, defect repair device 130D has a distalpatch 244 of a flexible, biocompatible material attached to a wire frame246, much like distal patches 206, 208, 210 of FIGS. 21-23. Wire frame246 may be continuous wire of stainless steel, Nitinol™, or otherbiocompatible, resilient metal or polymer, and may include a pluralityof loops 248 like those shown in FIGS. 21-23. Rather than being attachedto a proximal patch like the above-described embodiments, however,distal patch 244 of FIG. 24 is attached to a central hub 250, to whichare coupled a plurality of radially-extending struts 252 on the proximalside of patch 244 and parallel thereto. While defect repair device 130Dis pictured with four such struts in FIGS. 24A-24B, struts 252 may bebetween three and twelve in number. Struts 252 are Nitinol, stainlesssteel, or other flexible, resilient biocompatible metal or polymer, andare coupled to hub 250 in such a way that the outer ends 254 of struts252 are biased toward patch 244 and deflectable away from patch 244about an axis perpendicular to the central axis of hub 250. Anadditional patch (not shown) may be attached to struts 252 to providepatches on both sides of septum S, although in most cases, a singlepatch on the higher pressure side of the septum (the left side of theheart) is sufficient to prevent interatrial or interventricular bloodflow through a septal defect.

In the embodiment shown, the inner ends 256 of struts 252 are formed ina loop which acts as a torsion spring to bias the struts toward patch244. Alternatively, inner ends 256 may be straight and anchored directlyto hub 250, wherein each strut 252 acts as a leaf spring biased towardpatch 244. Optionally, distal struts 260 coupled to hub 250 may beprovided adjacent to or attached to patch 244, distally and parallel tostruts 252, so as to compressively engage septum S between the two setsof struts, as shown in FIG. 24B. In the embodiment shown, each of struts252 is formed with one of distal struts 260 from a single continuouslength of wire, with a first loop at the inner end 256 of each strut252, and a second loop at the inner end 262 of each distal strut 260. Aretainer 261, which may be a snap-ring, band, or loop of suture, retainsstruts 252 and distal struts 260 on hub 250. Struts 252, 260 may beround in cross-section, or rectangular so as to increase the moment ofinertia in the transverse direction so that the struts tend to bend onlyabout an axis perpendicular to the central axis of hub 250. Outer ends254, 264 of struts 252 and distal struts 260 may include a sharp point258 oriented generally perpendicular to the straight portion of thestrut so as to partially penetrate septum S, as shown in FIG. 24B.Points 258 may alternatively be made long enough so that the pointscompletely penetrate septum S, allowing visual inspection of strutdeployment by observing emergence of each point on the opposite side ofthe septum. In one embodiment, outer ends 254 are formed in a 270° loopso that points 258 attain a perpendicular orientation. Hub 250 includesa threaded hole 266 which may be coupled to an introducer shaft.

Defect repair device 130D of FIG. 24A is shown in FIG. 25A in acollapsed configuration within delivery shaft 134 for introduction intothe heart through access device 22. Hub 250 is threadably mounted to arod 273 attached to the end of an elongated tubular introducer shaft 268to facilitate deployment of repair device 130D within the heart. Patch244 and distal struts 260 are collapsed together distally of hub 250,while struts 252 are collapsed together proximally of hub 250. Springloops at the inner ends 256, 262 of struts 252, 260 bias the strutsoutwardly against the inner wall of delivery shaft 134. A retractionwire 270, which may be a length of suture or wire, is attached to theouter end 254 of each strut 252 and extend through the interior ofintroducer shaft 268. After deployment of repair device 130D, retractionwires 270 may by used to retract the device back into delivery shaft 134to reposition or remove the device. By tensioning retraction wires 270from outside of the patient's body, struts 252 are re-collapsed andrepair device 130 may be pulled back into delivery shaft 134.Preferably, retraction wires 270 are looped through outer ends 254 ofthe struts so that both ends of the retraction wires extend out of thebody through delivery shaft 134. In this way, once repair device 130D isdeployed satisfactorily, retraction wires 270 may be removed by simplypulling one end. Short lengths of suture or wire (not shown) may also beconnected between outer ends 254 of adjacent pairs of struts 252, and aretraction wire 270 then looped through each short length. Thisconfiguration helps to maintain spacing between struts 252 and preventtangling. Alternatively, a single retraction wire may extend through allof the loops at the outer ends of struts 252, with both ends of thesingle retraction wire extending out of the patient's body throughdelivery shaft 134.

FIG. 25B illustrates an exemplary embodiment of an actuator handle 249mounted to a proximal end of delivery shaft 134 for deploying repairdevice 130D. Delivery shaft 134 is slidably received within an axialbore 251 in a distal end of actuator handle 249. An actuator button 253is slidably mounted to a post 255 attached to a proximal end of deliveryshaft 134, and is biased outwardly by a spring 257. Button 253 extendsthrough an axial channel 259 in actuator handle 249, and has an enlargedinner portion 263 which is slidably received within detents 265 atspaced-apart positions along channel 259. In this way, button 253 islocked in position when enlarged inner portion 263 is received indetents 265, and to move delivery shaft 134, button 253 is pushed inwardand either proximally (to deploy repair device 130D) or distally (toretact repair device 130D). Detents 265 are positioned so as tocorrespond respectively with repair device 130D being fully retractedwithin delivery shaft 134, distal patch 244 being deployed from deliveryshaft 134, and struts 252 being deployed from delivery shaft 134.Introducer shaft 268 extends out of the proximal end of delivery shaft134 and is rotatably mounted to the proximal end of actuator handle 249.A rotatable knob 267 is mounted near the proximal end of introducershaft 268 and is exposed through a slot 269 in the side of actuatorhandle 249 to allow rotation of introducer shaft 268 for decoupling fromrepair device 130D. Retraction wires 270 extend through the interior ofintroducer shaft 268 and extend out of actuator handle 249 through ahole 271 in the proximal end thereof.

FIGS. 26A and 26B illustrate the deployment of defect repair device 130Dof FIGS. 24A-24B. Repair device 130D is delivered through access device22 (not shown) into the heart in the collapsed configuration of FIG. 25within delivery shaft 134. In the case of an atrial septal defect,delivery shaft 134 is introduced so that its distal end 136 is on theleft atrial side of septum S, as shown in FIG. 26A. Introducer shaft 268is then advanced distally relative to delivery shaft 134 until patch 244is deployed from the distal end 136 of the delivery shaft. Upondeployment, distal struts 260 and/or frame 246 (not shown) of patch 244spring outwardly to an expanded configuration in which patch 244 isgenerally flat and parallel to septum S within the left atrium. Deliveryshaft 134 and introducer shaft 268 are then pulled proximally so thatpatch 244 engages septum S and points 258 on distal struts 260 penetrateinto septum S. Delivery shaft 134 is then pulled further proximallyrelative to introducer shaft 268 so that struts 252 are deployed fromdelivery shaft 134, allowing them to spring outwardly and toward septumS, anchoring patch 244 in position as shown in FIG. 26B.

If the position of patch 244 is not satisfactory, retraction wires 270may be tensioned to retract struts 252 back into delivery shaft 136.Introducer shaft 268 may then be pulled proximally to retract patch 244back into the delivery shaft, or introducer shaft 268 may be pusheddistally to disengage patch 244 from septum S, then manipulated toreposition the patch at the desired location. Struts 252 are thenre-deployed in the manner described above. Once patch 244 is positionedsatisfactorily on septum S, retraction wires 270 are removed from struts252, introducer shaft 268 is decoupled from hub 250, and the introducershaft and delivery shaft 134 are removed from the heart. Access device22 is then removed from the heart, the penetration in the heart wall isclosed, and the procedure completed as described above.

It should be noted that in any of the foregoing embodiments of defectrepair device 130, a portion of the patient's own pericardium may beexcised and mounted to the frame or struts of the defect repair deviceas a patch. In an exemplary embodiment, endoscopic scissors and graspersare introduced through access ports 90 and used to cut and remove aportion of pericardium of suitable size to cover the septal defect.Exterior to the chest cavity, the pericardial patch is then sutured ontoa wire frame similar to frames 224, 226, 228 of FIGS. 21-23, or ontostruts like struts 252, 260 of FIGS. 24-26. If desired, two pericardialpatches may be mounted to two frames or two sets of strutsinterconnected by a hub to provide patches on both sides of the cardiacseptum. Once the pericardial patch is attached to the frame or struts,the defect repair device is introduced into the heart through accessdevice 22 and attached to the cardiac septum as described above.Advantageously, the use of the patient's own pericardium reduces therisk of biologic incompatibility and other potential complications ofartificial patch materials.

In another embodiment of the invention, illustrated in FIGS. 27-33, anapparatus and method are provided for closure of septal defects usingsutures, rather than patch-type defect repair devices. In thisembodiment, a plurality of needles 274 are mounted to a distal end 276of an introducer shaft 278. Needles 274 are held parallel to introducershaft 278 in a generally circular arrangement coaxial with theintroducer shaft. Needles 274 may be between 2 and 12 in number, andpreferably are 4, 6, or 8 in number, depending upon the size of thedefect to be closed. A length of suture thread 275 (best seen in FIG.28) extends between each pair of needles 274, each pair having oneneedle on opposite sides of an imaginary line separating needles 274into two equal groups.

Introducer shaft 278 is preferably a rigid material such as stainlesssteel for optimum control in manipulating and positioning needles 274from outside of the chest cavity. Alternatively, all or a distal portionof introducer shaft 278 may be a flexible material and may include meansfor deflecting or steering distal end 276, such as pull wires anchoredinternally to distal end 276 and extending through the introducer shaftto an actuator at the proximal end for selectively tensioning the pullwires. Introducer shaft 278 may be used to introduce needles 274 throughaccess device 22 into the right atrium RA, and through septal defect Dinto left atrium LA, as illustrated in FIG. 27. Needles 274 have sharpdistal tips 280 oriented so as to point in a proximal direction towardseptum S from left atrium LA, and are held removably at their proximalends 282 in needle holders 284 extending distally from the distal end ofintroducer shaft 278. Needle holders 284 comprise flexible rods ofstainless steel, titanium, Nitinol® (Raychem Corp.), or a biocompatiblepolymer, having a needle holding cup 285 (seen more clearly in FIGS.28-29) at their distal ends in which needles 274 are inserted.

An expandable element 286 is disposed concentrically within the spacesurrounded by needles 274 distal to introducer shaft 278. Expandableelement 286 may comprise an inflatable balloon having an interior incommunication with an inflation tube 288 extending through an innerlumen in introducer shaft 278. Alternatively, expandable element 286 maycomprise a rigid camming element such as a disk, cylinder, or ball fixedto the end of a movable shaft 288.

As illustrated in FIG. 28, expandable element 286 is expanded by, e.g.,introducing an inflation fluid through inflation tube 288. Expandablemember 286 urges needle holders 284 outward so that distal tips 280 arepointed toward septum S around the periphery of defect D.

With needle holders 284 in a radially-expanded position, introducershaft 278 is drawn proximally relative to access device 22 so thatneedle distal tips 280 penetrate septum S, as shown in FIGS. 29A-29B. Itcan be seen that cups 285 on needle holder 284 are held in an offsetrelationship to flexible rods 287 so that when rods 285 engage septum Sat the periphery of defect D, needles 274 are spaced outwardly apredetermined distance from the edge of the defect to ensure adequatespacing and "bite" on the septal tissue. Preferably, each needle 274penetrates septum S about 1-3 mm from the edge of defect D.

As best seen in FIG. 29B, introducer shaft 278 may comprise a pluralityof axial tubes 290 in which needle holders 284 are disposed. Needleholders 284 are slidable within tubes 290 so that needles 274 may bemoved proximally relative to tubes 290 until distal tips 280 enter theopen distal ends 292 of tubes 290. A distal portion of tubes 290 may beflared or widened to facilitate receiving needles 274. A means forcapturing needles 274 (not shown) is provided within tubes 290 neardistal ends 292, such as a porous mesh or screen of a biocompatiblematerial such as Gore-Tex®, cotton, or Dacron, which may be penetratedby distal tips 280 of needles 274. A barb 294 is provided on needles 274just proximal to distal tips 280 which may be caught in the needlecapturing means within tubes 290 to retain needles 274 therein. Onceneedles 274 are captured within tubes 290, introducer shaft 278 is drawnproximally relative to needle holders 284, pulling needles 274 throughseptum S. Expandable member 286 may then be deflated, and expandablemember 286 along with needle holders 284 are then pulled proximallythrough defect D. Introducer shaft 278 (to which needles 274 areattached at distal ends 290), introducer shaft 278, and inflation tube288 are then withdrawn from the heart through access device 22.

In an alternative embodiment, illustrated in FIGS. 30A-30B, the meansfor capturing needles 290 comprises an outer sleeve 296 slidablydisposed over introducer shaft 278. Outer sleeve 296 has a capture disk298 on its distal end which has a penetrable outer layer 300 comprisinga porous mesh, sponge, or screen of a biocompatible material such asGore-Tex®, cotton, or Dacron. To capture needles 274, as shown in FIG.30A, expandable member 286 is deflated, and outer sleeve 296 is sliddistally over introducer shaft 278 until distal tips 280 of needles 274penetrate outer layer 300 of capture disk 298. Barbs 294 are caught inthe porous material of outer layer 300. Outer sleeve 296 may then bedrawn proximally relative to introducer shaft 278 as shown in FIG. 30B,pulling needles 274 through septum S. Expandable member 286 and needleholders 284 are then withdrawn through defect D. Outer sleeve 296 (towhich needles 274 are attached), introducer shaft 278, and inflationtube 288 are then withdrawn from the heart through access device 22.

Capture disk 298 may be a flexible foam or solid material such asnatural or synthetic rubber (e.g. silicone), thermoplastic elastomer, orpolyurethane so as to be collapsible for introduction and removal fromthe heart through access device 22. Alternatively, capture disk 298 maybe an expandable member such as an inflatable balloon or expandablebasket which allows introduction and removal through access device 22 ina collapsed state, and expansion into an expanded state within the heartfor capturing needles 274. In either case, capture disk 298 hassufficient rigidity when expanded to allow needles 274 to penetrateouter layer 300 without the capture disk over-flexing or collapsing.

As a further alternative technique for capturing needles 274 after theyhave penetrated septum S, needles 274 are removed from cups 285 bypushing distally on needle holders 284. Expandable member 286 is thendeflated and withdrawn through defect D along with needle holders 284.Introducer shaft 278, inflation tube 288 and needle holders 284 are thenwithdrawn from the heart through access device 22, leaving needles 274extending through septum S. An elongated endoscopic needle driver (notshown) may then be introduced through access device 22 into the heart,and, under visualization with ultrasound, an endoscope, or fluoroscope,the needle driver is used to grasp each needle 274 and pull it throughseptum S and out of the heart through access device 22.

When needles 274 have been withdrawn from the heart, at least one, andusually two to six loops of suture (depending upon the number of needlepairs used), will have been formed across defect D, as illustrated inFIG. 31A-31B. Suture threads 275 are long enough, usually at least about30 cm in length, to extend across defect D and through septum S, withboth ends extending out of the heart and chest cavity through accessdevice 22. In this way, sutures 275 may be tensioned to draw defect Dclosed, and knots formed extracorporeally and pushed into the heartthrough access device 22 using an elongated endoscopic knot pusher. Asshown in FIG. 31C, a plurality of knots 304 are formed in each suture275 and pushed against septum S to ensure tight closure of defect D.Sutures 275 are then trimmed using elongated endoscopic scissorsintroduced through access device 22. Complete closure and absence ofshunting is verified using transesophageal echocardiography or one ofthe other visualization techniques outlined above.

An alternative embodiment of a septal defect repair device according tothe invention is illustrated in FIGS. 32A-32D. This embodiment of defectrepair device 130 is in many respects similar to that described above inconnection with FIGS. 27-30, the major difference being that needleholders 284 are pre-shaped so as to be biased outward into theradially-expanded configuration shown in FIG. 32B. Needle holders 284may be stainless steel, a shape-memory alloy such as nickel-titanium, oranother flexible and resilient metal or polymer. Needle holders 284 maybe long enough to extend entirely out of the body cavity through accessdevice 22, or they may be attached to an introducer shaft (not shown) asin the above embodiments. As shown in FIG. 32A, a restraining sleeve 306is slidably positioned over needle holders 284 and may be advanceddistally relative to the needle holders to urge needle holders 284inward into a collapsed position for introduction through access device22 and through defect D. A distal portion of needle holders 284 ispre-shaped in an outward bend or curve so that, when restraining sleeve306 is retracted, needle holders 284 return to a radially-expandedposition in which needles 274 are positioned outside of a circle definedby the diameter of defect D. As in previous embodiments, needle holdingcups 285 are offset relative to rods 287 of needle holders 284 so thatneedle holders 284 move outward until rods 287 engage septum S at theperiphery of defect D. Needles 274 are then positioned at apredetermined spacing from the edge of defect D to ensure adequate"bite" into septal tissue.

The embodiment of the defect repair device of FIGS. 32A-32D is otherwisesimilar to the embodiments of FIGS. 27-31 described above. As shown inFIGS. 32C-32D, after needles 274 have been drawn through septum S arounddefect D, the needles are captured by means of a capture disk 298 with aporous outer layer 300, or by another means such as endoscopic needledrivers introduced through access device 22, as described above. Aftercapture of needles 274, restraining sleeve 306 is advanced distally tocollapse needle holders 284 inward, and needle holders 284, restrainingsleeve 306, capture disk 298, and needles 274 are withdrawn from theheart through access device 22. This leaves sutures 275 extending acrossdefect D as shown in FIGS. 31A-31B; sutures 275 are then tensioned,knots are formed in sutures 275 extracorporeally, and the knots arepushed into the heart and against septum S using an endoscopic knotpusher, closing defect D as illustrated in FIG. 31C. A suitable knotpusher is disclosed in copending application Ser. No. 08/288,674,entitled "Surgical Knot Pusher and Method of Use," filed Aug. 10, 1994,now U.S. Pat. No. 5,601,576 the disclosure of which is herebyincorporated herein by reference.

It should be noted that while the method of the invention has beendescribed in connection with the repair of atrial septal defects, itwill be understood to those of ordinary skill in the art that theinvention will be equally applicable to repair of ventricular septaldefects, patent ductus arteriosus, and other defects of the heart.Access device 22 may also be introduced through a wall of the rightventricle, left atrium, pulmonary artery, or pulmonary vein rather thanthe right atrium. Alternatively, access device 22 may be introduced intothe right atrium as previously described, with access to the rightventricle or pulmonary artery obtained from the right atrium through thetricuspid valve. Devices and techniques similar to those described abovefor atrial septal defects may be used for repairing ventricular defectsand patent ductus arteriosus. Other repair devices designed specificallyfor ventricular septal defects and patent ductus arteriosus which areuseful in the method of the present invention are described in U.S. Pat.No. 3,874,388, which has been incorporated herein by reference. Thedefect repair devices of the invention may also be used to repair thepenetration in the heart wall made by access device 22, and to repairother types of defects, holes, incisions, or punctures in other organsand tissue structures.

In addition to repair of atrial and ventricular septal defects andpatent ductus arteriosus, the devices and methods of the invention alsofacilitate various other intracardiac interventions, includingelectrophysiological mapping and ablation. FIGS. 33 and 34 illustratetwo embodiments of an electrophysiological device according to theinvention. In the embodiment of FIG. 33, an electrophysiology device 310is introduced through access device 22 into a chamber C of the heart H.Electrophysiology device 310 includes a rigid shaft 312 having a distalend 314 and a proximal end 316. Usually, at least one inner lumen (notshown in FIG. 33) extends through shaft 312 between distal end 314 andproximal end 316. A flexible and pre-shaped or deflectable tip 318 isattached to distal end 314. A handle 320 is attached to proximal end316. A plurality of conductive electrode bands 322 are mounted todeflectable tip 318, each electrode band being separately electricallycoupled by means of wires (not shown) within shaft 312 to a connector324 on handle 320. Connector 324 is adapted to be coupled to a cord 326which is connected to a radiofrequency generator or electrocardiographymachine (not shown) used in conventional mapping and ablationprocedures. An actuator 328 is slidably coupled to handle 320 and isconnected to deflectable tip 318 by at least one pull wire (not shown)extending slidably through an inner lumen in shaft 312 and attachedinternally to deflectable tip 318 near its distal end 330. In this way,sliding actuator 328 proximally on handle 320 deflects deflectable tip318 into a curved configuration, as illustrated in FIG. 33. Of course,various types of actuators may be used for deflection of deflectable tip318, including shapable or deflectable handles, joy-sticks, levers,pistol grips, and the like. In addition, shaft 312 may be rotatablycoupled to handle 320, and a rotator knob (not shown) may be attached toshaft 312 near proximal end 316 to allow deflectable tip 318 to berotated about the longitudinal axis of shaft 312. Exemplary mechanismsfor actuation and deflection of deflectable tip 318 and other featureswhich may be incorporated into electrophysiology device 310 aredisclosed in U.S. Pat. Nos. 4,960,134, 5,318,525, 5,368,592, 5,364,351,and 5,313,943, which are incorporated herein by reference. While thesepatents disclose highly flexible, endovascular electrophysiologycatheters for introduction transluminally from a peripheral vessel intothe heart, it will be understood to those of ordinary skill in the artthat any of the features of endovascular electrophysiology devices maybe easily incorporated into the more rigid, thoracoscopicelectrophysiology device of the invention.

Shaft 312 has a length which is long enough to extend from withinchamber C of heart H through access device 22 outside of the patient,usually being 20-30 cm in length. Shaft 312 is preferably rigid, usuallybeing made of stainless steel (with insulated electrodes and wires) orof a rigid biocompatible polymer, so as to facilitate precise andcontrollable positioning of deflectable tip 318 from outside of thechest cavity using handle 320. Deflectable tip 318 is a non-conductive,flexible and biocompatible polymer such as polyurethane, silicone,thermoplastic elastomer, polyolefin, polyamide, or a fluoropolymer.

In an alternative embodiment, illustrated in FIG. 34, electrophysiologydevice 310 includes, rather than a deflectable tip 318 as in theprevious embodiment, an expandable electrode array 332 attached todistal end 314 of shaft 312. In a preferred embodiment, electrode array332 comprises a plurality of electrode bands 334 mounted in spaced-apartpositions to an expandable basket 336. Expandable basket 336 includes aplurality of axially-oriented beams 338, which are preferably anon-conductive, flexible and resilient polymer such as a polyolefin orpolyamide, or a metal such as stainless steel or nickel-titanium alloywith an insulative coating to electrically isolate each of electrodebands 334. Beams 338 are coupled together at their distal ends 340, andat their proximal ends are attached to shaft 312. In one embodiment,shaft 312 is a polymeric tubular extrusion, and beams 338 are formedintegrally with shaft 312 as part of the same extrusion, by, for examplecutting axial slits in a distal portion of shaft 312. As in theembodiment of FIG. 33, each of electrode bands 334 is independentlyelectrically coupled to connector 324 by a wire extending through aninner lumen in shaft 312.

Expandable basket 336 is movable between a collapsed configurationsuitable for introduction through access device 22 and an expandedconfiguration in which electrode bands 334 are spread apart into athree-dimensional array, positioned at various distances both radiallyoutward from and distal to shaft 312, as shown in FIG. 34. In this way,electrode bands 334 may be simultaneously positioned at a number oflocations around the interior wall of chamber C. To move expandablebasket 336 between the collapsed and expanded configurations, a varietyof different mechanisms may be utilized. In one embodiment, a pull wire342 is coupled to distal ends 340 of beams 338, and extends slidablythrough a lumen in shaft 312 for attachment to actuator 328. In thisway, actuator 328 may be slid in a proximal direction to exert acompressive force on beams 338, causing beams 338 to bow outward intothe expanded configuration. When pressure is released from actuator 328,beams 338 recoil to their unstressed, straight configuration.

In addition to the embodiment illustrated, various types of structuresmay be used for electrode array 332, including those disclosed in U.S.Pat. Nos. 4,699,147, 4,660,571, 4,628,937, 4,522,212, 5,313,943, and5,327,889, which are incorporated herein by reference. Although thesepatents describe endovascular electrophysiological catheters, it will beunderstood to those of ordinary skill in the art that the electrodearray configurations, structures and deployment mechanisms disclosed maybe easily adapted to the larger diameter, shorter and more rigidthoracoscopic electrophysiology device of the present invention.

Electrophysiology device 310 may be used for either mapping or ablationof conduction pathways in the heart. In use, electrophysiology device310 is introduced into chamber C of heart H through inner lumen 30 ofaccess device 22. Chamber C may be the left or right ventricle, or leftor right atrium, depending upon where the target site for mapping orablation is located. If the target site is in the higher pressure leftside of the heart, access device 22 is provided with a hemostasis sealin inner lumen 30 to allow introduction of electrophysiology device 310without significant leakage of blood. For the device of FIG. 33,deflectable tip 318 is substantially straight and undeflected duringintroduction. For the device of FIG. 34, expandable basket 336 is in acollapsed state in which beams 338 are substantially straight andaligned with shaft 312 during introduction. Once introduced into chamberC, deflectable tip 318 is deflected (in the embodiment of FIG. 33) orexpandable basket 336 is expanded into an expanded configuration (in theembodiment of FIG. 34) by sliding actuator 328 on handle 320. Undervisualization using transesophageal echocardiography or one of the othertechniques described above, electrodes 322, 334 are positioned at thedesired location against the wall of chamber C by manipulating thedevice with handle 320. The relatively short distance between the userand the interior of chamber C, as well as the rigidity of shaft 312,facilitate exceptionally controllable and precise manipulation of thedevice relative to endovascular catheter-based electrophysiologydevices.

When electrodes 322, 334 have been positioned at the desired site inchamber C, conduction pathways can be mapped by measuring the electricalpotential between selected electrodes with sensitiveelectrocardiographic equipment. When aberrant pathways are found, theymay be ablated by applying radiofrequency current from a radiofrequencygenerator through a selected electrode or electrodes onelectrophysiology device 310 to the myocardial tissue. These techniquesmay be used to diagnose and/or treat ventricular tachycardias,ventricular fibrillation, supraventricular tachycardias such asWolff-Parkinson-White Syndrome, atrial fibrillation, and otherconduction-related diseases. Ablation may also be performed using amedical laser transmitted through an optical fiber introduced into theheart through access device 22, by techniques analogous to theendovascular laser ablation techniques disclosed in U.S. Pat. No.5,104,393, which is incorporated herein by reference.

In addition, thoracoscopic, endovascular, or open surgical devices andtechniques may be used in conjunction with the devices and methods ofthe present invention. For example, electrophysiology device 310 may beused to ablate selected cardiac tissue within the heart based on mappinginformation generated using endovascular mapping catheters orthoracoscopic mapping devices. Alternatively, electrophysiology device310 may be used for mapping conduction pathways in the heart, which arethen treated by means of thoracoscopic, endovascular, or open-chesttechniques. Such a technique could be used for treatment of ventricularand supraventricular tachycardias. Similarly, to treat atrialfibrillation, after intracardiac mapping has been performed using theelectrophysiology device of the invention and/or endovascular mappingtechniques, mechanical, laser, or RF cutting devices may be introducedthrough access device 22, and precise incisions or ablation lines may bemade in the myocardium to create a directed conduction pathway betweenthe sinoatrial node and the atrioventricular node to perform a Cox"maze" procedure.

After the electrophysiology procedure is completed, deflectable tip 318is returned to its straightened configuration or expandable basket 336is collapsed so that beams 338 are again straight and aligned with shaft312. Electrophysiology device 310 is then removed from the chest cavitythrough access device 22.

In addition to repair of atrial and ventricular septal defects andcardiac mapping and ablation, the devices and techniques of theinvention are useful in a variety of other intracardiac procedures.Low-profile, elongated instruments may be introduced through accessdevice 22 to inspect and repair the mitral, tricuspid, pulmonary oraortic valves. Commissurotomy may be performed, for example, byintroducing a cutting instrument and incising the valve commissures toseparate the valve leaflets. Transmyocardial laser revascularization maybe performed by introducing a laser-transmitting optical fiber throughaccess device 22 and using the laser to drill new blood-carryingconduits into the myocardium from within the heart chambers. Cutters,graspers, biters, and the like may be introduced through access device22 to cut and remove unwanted tissue or other material from the heartand great vessels, such as thrombus (e.g. pulmonary thrombectomy),myxomas, neoplasms, vegetations, calcifications, and tissues affected byhypertrophic obstructive cardiopmyopathy. Catheters may also beintroduced through access device 22 for positioning in the pulmonaryartery, coronary sinus, or other locations for perfusion, drug delivery,fluid venting, and other purposes. Advantageously, many of theseprocedures can be performed while the heart is beating, without the needto place the patient on cardiopulmonary bypass and to inducecardioplegic arrest. In addition, these procedures can be performedwithout the need for a median sternotomy or other gross thoracotomy,reducing greatly the pain, recovery time, morbidity, and mortalityassociated with open heart surgery.

While the above is a complete description of the preferred embodimentsof the invention, it will be understood to one of ordinary skill in theart that certain modifications, substitutions, improvements andadditions may be made without departing from the scope thereof, which isdefined by the appended claims.

What is claimed is:
 1. A method of performing an electrophysiologicalablating procedure to ablate cardiac tissue in an interior chamber of apatient's heart, the method comprising steps of:forming a first openingin a patient's chest, the first opening passing through the chest walland into the patient's thoracic cavity; forming a second opening in thewall of the patient's heart, the second opening passing through the wallof the heart and into an interior chamber of the heart; providing acardiac access device having a distal end and a lumen for receiving anelectrophysiological instrument; positioning at least the distal end ofthe cardiac access device through the first and second openings and intothe interior chamber of the heart; providing an electrophysiologicalablating instrument comprising at least one electrode configured todeliver electrical current, the electrode being coupled to a source ofelectrical current; positioning the electrophysiological ablatinginstrument in the lumen of the cardiac access device so that at leastthe electrode extends out of the distal end of the cardiac accessdevice; and contacting cardiac tissue with the electrode and deliveringcurrent to the tissue to ablate at least selected portions of thetissue.
 2. The method of 1, wherein the electrode of theelectrophysiological ablating instrument is coupled to a source ofradiofrequency current, and the radiofrequency current is delivered tothe cardiac tissue through the electrode.
 3. The method of claim 1,wherein the electrophysiological ablating instrument comprises aplurality of electrodes which contact and deliver current to the cardiactissue.
 4. The method of claim 1, wherein the first opening is formed inthe chest wall so as to pass through an intercostal space betweenadjacent ribs, and the cardiac access device is positioned through theintercostal space and through the second opening in the wall of theheart.
 5. The method of claim 4, wherein the patient's ribs and sternumremain substantially intact during each of said steps.
 6. The method ofclaim 1, wherein said steps are carried out while the patient's heart isbeating, and further comprising the step of forming a hemostatic sealbetween the cardiac access device and the wall of the heart to inhibitblood loss through the second opening.
 7. The method of claim 1, furthercomprising the step of deflecting a distal end of theelectrophysiological instrument to position the electrode adjacent aninterior wall of the heart.
 8. A method of performing anelectrophysiological mapping procedure in an interior chamber of apatient's heart, the method comprising steps of:forming a first openingin a patient's chest, the first opening passing through the chest walland into the patient's thoracic cavity; forming a second opening in thewall of the patient's heart, the second opening passing through the wallof the heart and into an interior chamber of the heart; providing acardiac access device having a distal end and a lumen for receiving anelectrophysiological instrument; positioning at least the distal end ofthe cardiac access device through the first and second openings and intothe interior chamber of the heart; providing an electrophysiologicalmapping instrument comprising at least two electrodes configured tocontact cardiac tissue, the electrodes being coupled to a device fordetecting electrical potential between the electrodes; positioning theelectrophysiological mapping instrument in the lumen of the cardiacaccess device so that at least the electrodes extend out of the distalend of the cardiac access device; and contacting cardiac tissue with theelectrodes on the electrophysiological mapping instrument and detectingthe electrical potential between the electrodes to map conductionpathways in the cardiac tissue.
 9. The method of claim 8, wherein thefirst opening is formed in the chest wall so as to pass through anintercostal space between adjacent ribs, and the cardiac access deviceis positioned through the intercostal space and through the secondopening in the wall of the heart.
 10. The method of claim 9, wherein thepatient's ribs and sternum remain substantially intact during each ofsaid steps.
 11. The method of claim 8, wherein said steps are carriedout while the patient's heart is beating, and further comprising thestep of forming a hemostatic seal between the cardiac access device andthe wall of the heart to inhibit blood loss through the second opening.12. The method of claim 8, wherein the contacting step is carried out bymoving the electrodes from a first position in which they are out ofcontact with the cardiac tissue to a second position in which they arein contact with the cardiac tissue.
 13. The method of claim 12, whereinthe electrophysiological instrument comprises an expandable mechanismsupporting the electrodes, and the expandable mechanism is moved from acollapsed orientation to an expanded orientation to move the electrodesfrom the first position to the second position and into contact with thecardiac tissue.
 14. The method of claim 8, further comprising, aftersaid contacting step, steps of:providing an electrophysiologicalablating instrument comprising at least one electrode configured todeliver electrical current, the electrode being coupled to a source ofelectrical current; positioning the electrophysiological ablatinginstrument in the lumen of the cardiac access device so that at leastthe electrode extends out of the distal end of the cardiac accessdevice; and contacting cardiac tissue with the electrode and deliveringcurrent to the tissue to ablate at least selected portions of thetissue.